What is a diffraction grating?

A diffraction grating is a device designed to disperse light into its constituent colors or wavelengths by using multiple closely spaced slits. When light encounters a diffraction grating, it interferes with itself as it passes through these slits, leading to the formation of a spectrum. This occurs because different wavelengths of light are bent at different angles when they pass through the slits, allowing them to separate and produce distinct spectral lines.

The functionality of a diffraction grating is critical in various applications, such as spectroscopy, where it is used to analyze the spectral content of light emitted or absorbed by substances. This capability to produce detailed light spectra is what distinguishes diffraction gratings from other optical elements.